FIGS. 10, 11 and 12 show a conventional carriage cart. This conventional art is similar to those disclosed in, for example, Patent Document 1 and Patent Document 2. The carriage carts have a structure provided with a turntable 3 which is pivotally supported on a main body 2 of the carriage cart so as to be horizontally turnable, or horizontally turnable and vertically extendable, and a tab 21 projecting forward from a front frame. The carriage carts have a plurality of rollers 5 pivotally supported at the bottom thereof. At least four carriage carts are used to support a heavy object, such as a piece of furniture, by inserting the carriage carts into four corners underneath the heavy object. The carriage carts can integrally move with the heavy object by the load acting from the heavy object.